FIG. 9 is a drawing showing an example of the structure of a conventional spiral wound battery (Patent Reference No. 1). As shown in the drawing, a spiral wound battery typically comprises a sheet-like cathode on which cathode active material (cathode compound layer 8) is formed, a separator 4, and a sheet-like anode on which anode active material (anode compound layer 10) is formed. Furthermore, these are respectively wound in layered fashion such that uncoated regions (regions 7, 9 uncoated with compound layer) at mutually opposite edge portions of the anode and the cathode extend beyond the separator when housed within the battery casing. Uncoated regions 7, 9 at which active material (cathode compound layer or anode compound layer) is not present are provided at these edge portions of the electrodes, current collector 5, 6 being connected by welding or the like to these uncoated regions 7, 9 so as to permit connection to the respective terminals of the battery casing.
Although the spiral wound battery shown in the example of the drawing has a flattened profile, the electrodes thereof being wound in substantially planar fashion, batteries of the cylindrical type (Patent Reference No. 2), which are wound in substantially cylindrical fashion, employ more or less the same basic structure and manufacturing method, these two types of battery differing only with respect to the fact that differently shaped mandrels are employed during winding of the electrodes.